Technical Field
The present invention relates to a surface light source device and a transmission display device.
Discussion of the Background
Conventionally, illumination for a liquid crystal display (LCD) panel has been provided in such a manner that a light is applied from a side of the LCD panel with a cathode-ray tube, or a light is applied from a back surface with a parallel cathode-ray tube. A constant distance is provided between the cathode-ray tube and the LCD panel, and a light guide plate and a diffusion plate are disposed between them together with a plurality of sheets to converge the light on them.
Furthermore, recently, the LCD panel has been more likely to use a light emitting diode (LED) having point light sources which independently emit three light primary colors such as red, green, and blue, instead of the cathode-ray tube (refer to patent documents of Japanese Unexamined Patent Application Publication No. 2008-66086, Japanese Unexamined Patent Application Publication No. 2011-159632, and Japanese Unexamined Patent Application Publication No. 2011-204371). This LCD panel is used in a television or monitor and has been increasingly thinned.